Box stacking mechanism



2,609,l l l Sept. 2, 1952 B. n. DAVES ETAL Box SMOKING MECHANISM 4Sheets-Sheet" 1 Filed Nov. 22,. 1946 Bnnentors.

Bu @MW (Ittorneg Sept. 2, 1952 B. R. DAvEs ETAL Box STACKING MEcHANisM 4Sheets-Sheet 2 Filed NOV. 22, 1946 nventors,

attorney SePt- 2, 1952 B. R. DAvl-:s ETAL 2,609,111

' Box sTAcxrNG MECHANISM Filed Nov. 22, 1946 4 Sheets-Sheet I5Srwentors.

Gttorneg Sept. 2, 1952 B. R. DAvEs Erl-Al.v 2,609,111

Box sTAcxING MEcHANIsM Filed Nov. 22, 1946 Sil/Mete i. @A1/5, lMiei/VL'ZIQV/Ms; J5 J5 nventors.

Gttomeg Patented Sept. 2, 1952 Bruner R; Davos and Warren L. Irvine,vv dClaremont, Gali. A

Application November 22., 1946, Serial No. '711,524V

This invention relates vto means for "receivingV successive ones of apluralityk yoie boxes and arranging thesame in vertically stackedrelation,

and pertains more particularly to a device which will receive thesuccessive 'boxes and' place them successively at thebottom of a stackwhich is being formed, until the desired number ofboxes Y in thestackhave been arranged, and then'cause the assembled stack to -bedischarged from the device as a unit.

One of the particular objects of this invention is to provide adevicewhich will arrangea plurality of boxes in stacked relation withoutexcessive jarring or disturbance of the contentsfof the boxes, afeature'ofV particular importance where thev device-r is employed to'Ystack boxes of oranges or'other fruit which aresubject'to decayI andspoilage in the event off bruising. Y

"A further object of tlieinvention-` is to provide a devicev ofv thecharacter described,-'which maybel'utilized in close association withafdeliveryl conveyor `in position to receive boxesdelivered thereby, toreceive and arrange suchl boxes in stacked relation, and deliver thestacked assembly, ina substantially vautomatic* fashion;

In the handling of boxes-containing fruit, such as oranges, itisfnecessary in the conservation of space to stack the `boxes to asgreata height as may be accomplished by manual labor, and where the boxeshave not beenflidded, i. e. thel pack made-secure, the fruit isnecessarilyloose and is subject todislodgment to alevel above thatcp ofthe box as a box is literally thrown on top` of a fairly high stack.When the next box-"is tossedpn top of a box containing such dislodgedfruit, ther-ruit projecting above the top of the box is subject tobruisingv and consequent rapid spoilage. In view of this' typefofdiiiicultyin the handling of boxesv containing loosely packed fruit,itis a particular object of this invention to provide adevice whichwillY formv a stacksof boxesfby placing the succeeding boxes atthebottom of the stack as it is being formed, under conditionsA such thatthe bottom box' in processzof stacking isnever subjected to forces ormovement such as to dislodge the fruit from the positiony it occupieswhenv deliveredtoY thev stacking device, thereby avoiding fruit `damageyof the type above described.

The device of the present invention may comprise, in general, a guidemeans `definingavertically Vextending hollow shaft khaving-internaltransverse dimensions consonant with'l thetransverse dimensions of theboxes tobe stacked .and provided adjacent its lowerv end' with anopening' through which the boxes `may be supplied. iny succession at agiven loading level', togetherv with carriage means adapted -toreceive aso` delivered boxlandY raisel the same upwardly within the hollowfsh'afttota locating level'. Thendevice further comprises means forreturning-the; carriage to the loading level `forfthereception'of' a.second box, carrying 'such secondA box' upwardly typical embodiment, orwill be apparent from,y

into contact with the rst box locating level and thereafter raise therst box and't'he second Vbox in af stacked' relationship until the'secondY box is disposed at the locating level; Means are provided forArepeating this procedure until the desired number of boxes have beendisposed in stacked relation, after which the entire stack isflowered tothe floor or any other suitable levelr for discharge from the shaft asvan assembledstack.4

VOther features of the invention will be brought out` in the ensuringspecic description of a suchdescription. The accompanying drawingsillustratethis typical embodiment in detail, and referring thereto: v

Fig.. 1 is a three-quarter view of-the stacking device of thisinvention, taken from the loading side; Y Y

Fig- 2v is a three-quarter view taken from the discharge lside;

Fig. 3 is a partly broken away vertical section as takenon line 33fofFig. 2;

Fig. 4 is a fragmentary vertical section in the sameplane as the leftside of Fig. 3, taken in the Vicinity of line IG-6 in Fig. 3, showing aposition adopted vby the boxes during the stacking operation;

Fig. 5'is a View corresponding to Fig. 4 showing an` alternativeposition adopted by the boxes;

Fig; Gis a `fragmentary transversesection asV taken on-line--dn Fig. 3;

Fig.` '7 is a ragementary vertical section as taken on line 1-1 in Fig.3;

Fig.f8 is a fragmentary transverse section as taken: on line 8;-8in-Fig. 6;

Fig. 9' l isa 4fragmentary vertical section as takenon line 9-9 of Fig.3;

Fig. 1'0 isa diagrammatic showing of one side of the stacking deviceshowngthe relative location of operating circuit control switches whichmaybe employed to secure a substantially automaticoperationof thedevice; and

Fig.` 1l is a schematic showing'of a form of control circuit which maybe employed for operation of the .stacking device of this invention.

Referringto the drawings, the device may comprisea plurality of verticalmembers l'arranged to denne a vertically extending shaft 2V havinginternalk dimensions consonant with the transversedimensions of thestyle of box which is to be handled in a'stacking operation. Thedrawings show various boxes in process of being stacked, which areindicated generally by the reference numeral 3.

The members IA are mounted on or securedto a 'oor'structure it above achain conveyor 5 havinglanactive run located slightlyy above they floorlevelr in position to carry away a stack of boxes lowered thereupon;such chain conveyors beingv in common use inA packing houses, nodetailed showingythereof is made herein. At a suitable heightabovetheool, aS may be required for disposed at the Y 3 cooperation witha particular conveyor assembly, the side of the shaft 2 is cut away toprovide a receiving opening 6 through which boxes may be passed from anadjacent conveyor 1. Usually a main conveyor will be provided as at 8which will carry boxes to any given stacking device, and` the conveyor'I will be employed to receive the boxes from the main conveyor 8 and tocarry` them to the shaft 2.

Within the shaft 2 a vertically movable carriage is provided for thepurpose of receiving the boxes delivered through the opening 6, and thiscarriage may comprise a pair of spaced platform members 9 threadedlymounted on lead screws I0 at the respective sides of the structure, thelead screws being journaled at their bases as at I I and provided withpower operating means I2 which may conveniently be located at the upperend of the frame dened by the uprights I. Each of the platform membersis provided with a plurality of supporting rollers I3 so positioned asto underlie the respective longitudinal ends of the nether surface ofthe box 3 delivered from the conveyorV 'I through the opening 6.Suitable guide rollers I4 may be provided for engagement with theadjacent uprights I, to cause the platform members 9 to be constrainedin relative position during the rotation ofthe lead screws I in theoperation of the device. l

When a box is delivered from the conveyor 'I through the opening 6 ontothe carriage means defined by the platform members 9, the operatingmeans I2 is caused to be energized in such direction as to move thecarriage means upwardly in a start of the stacking operation. Referringto Fig. 3 in particular, the box received by the carriage means iscaused to be carried upwardly to approximately one and one-half boxheights, adjacent which level means are provided for supporting the boxagainst downward movement while the carriage means is lowered to theloading level as -dened by the conveyor "I, Such supporting means,hereinafter referred to as locating means, is of a character such as tobe readily moved out of locating position with respect to a superior boxwhen a succeeding box is raised toward Vlocating position. By way ofexample-we have illustrated such locating means as com-l prising aplurality of locating rollers I mounted on suitable brackets I'Gattached to the respective corners of the framework defining the shaft 2and adapted to engage a box at its four corners. These rollers arecarried by axial pins I1 located in guide slots I8 so shaped as topermit upward and outward movement of the rollers upon engagement by theupper edges of an inferior box, the amount of movement permitted by theguide slots I8 being such as to locate the inwardly directed peripheriesof the rollers I5 inwardly of the ends of the box 3 in their loweredposition and outwardly of the ends of the box in their raised position.The slots I8 are preferably provided with vertically extending inner endportions I8a adapted to resist outward movement of the rollers I5 underthe load imposed by a box 3 (Fig. 3).

We preferably provide means for lifting the rollers I5 clear of theboxes 3 to a position such as they will not interfere with they lateraldischarge of a stack from the shaft 2 as hereinafter described, and suchmeans may comprise a solenoid I9 mounted on each of the brackets I6 andhaving an actuating rod I9a carrying a f oot 20 adapted to engage thelower edge of the roller I5, the solenoid being mounted on the outsideof t the bracket andy extending into the space within the bracketinto'engage'm'e'nt with thevroller I5 through a slot I6a in saidbracket. This structure t is omitted in Figs. 1, 2, 4, and 5, shown insmall scale sectionally and in elevation in Fig. 3, and shown in greaterdetail in Figs. 6 and 8. Operation of the solenoid I9 is adapted tocause the roller I5 to adopt the dot-dash position of Fig. 8. Itis notnecessary that the solenoid be of sufcient strength to pull the rollerI5 out from under a located box 3', inasmuch as it is only necessary tolift the rollers I5 clear of a box when the roller-box relation is thatof Fig. 4.

When the carriage means is raised to place a box ,on the locatingYrollers, the rollers move upwardly and laterally. after the mannershownin Figs. 4 and 8, and :when the nether edges of the box clear therollers, the rollers drop inwardly in position Vto be engaged by thecorners of the box as the carriage means is returned toward the loadinglevel, as shown in full lines in Fig. 8. When a box has already beenlocated on the rollers I5, the next succeeding box will engage therollers (see dot-dash lines 3 in Fig. 8) and push them out ofcontactwith the box which they had been supporting, and the box or boxesabove the position of the rollers will fall against the upper edge ofthis next succeeding box. 'I'he continued upward movement of thecarriage means then carries the whole stack upwardly until the loweredge of the lowest box clears the vrollers I5, as to the position ofFig. 5, at which timey the carriage means is lowered until the bottomcorners of such box engage and are located by the rollers, after whichthe carriage means is returned to the loading level.

Assuming that the boxes are to be stacked nine in a stack (a heightcommonly in use in citrus Vpacking houses), only eight boxes have to becarried as high as the locating level defined by the rollers I5 inasmuchas the ninth box has merely Ato be carried upwardly an amount sufficientthatthe rollers I5 are pushed out of the way and the top eight boxesreleased into engagement withthe top of the ninth box. (To convenientlycontrol the operating drive mechanism I2, circuit control means can belocated in position to be engaged by the top box of a series instead ofrequiring the carriage means to be raisedl past the locating rollers tothe locating level, as will hereinafter more particularly be described.)After the desired number of boxes have been placed in stacked relation,the entire stack is then lowered by lowering the carriage means clear tothe floor so that the bottom box of the stack (as shown in dot-dashlines at 3a in Fig. 3) is brought into contact with the chain conveyor5. The downward movement of the platform members 9 is preferablyslightly greater than that just sufficient to place the bottom wall ofthe bottom box on the conveyor 5, so as to insure that there will be noopposition to the withdrawal of the stack.

Inasmuch as the stack is withdrawn as a unit, we .preferably providemovable guide means or gates 2I at the rearward side of the shaft 2,which will function to retain the stacked boxes within the shaft 2 untilit is desired to remove the Ystack as a unit, and these gates 2I may bepivotally mounted on the rearward frame members I, as at 22, and may beoperated through the agency of a gear and crank assembly 23 locatedbelow the floor level and operated by a lever arm 24 whichis engageableby the bottom box of the stack as.` the stack is lowered to the positionshown acca-11.1y

in. 'dot-dash lines in Fig., This gateoperating mechanism isillustratedin greater' .detail in Fig. 9, and may comprise the lever 24which is linked through arm 25 to a bell crank 26 carried on atransverse shaft 21 carrying a. bevel gear 28 meshing with a bevel gear29 .carried on an operatingshaft 3I secured to one of the gates 2|, it

being. appreciated that a drive assembly for eachv of the gates may beprovided, or that one of the gates. may be direct-driven and the otheroperated `by a linkage mechanism.

. When the stack of rboxes has been withdrawn from the shaft 2 by thechain conveyor 5, the lever 24 will be returned to the full lineposition of Fig'. 9, as through the agency of an operatingspring 32, andthis return movement may be utilized to institute upward movement of thecarriage means to the loading level.

The drive means I2 is illustrated as comprising areversible electricmotor 33 driving a cross shaft 34 which is geared to the operating orlead screwspl at gear boxes 35. Fig. 11 shows one form of voperatingcircuit which may be employed to secure a fully automatic operation ofthe stacking mechanism, although it will be appreciated that the devicemay be manually operated by the provision of conventional up and downswitches available tothe operator who-iis responsible for selecting aparticular type of box-off the conveyor 8 and causing it to move overthe conveyor 'I into the shaft 2. Fig. 10 represents the location of aplurality of switches' whichare operable by the carriage means or theboxes in the stack, S1 representing a normally Open double-pole switchlocated so as to be actuable by -a jbox 3 when it is received by thecarriage. means after delivery from thev conveyor 1.- It is intendedthat thisswitch willremain in closed or operated condition so long as abox is present on the carriage means. `he represents a doublepole switchhaving a set of normally closed contacts anda set of normally opencontacts located so as to *be operable by one of the platform members 9when the carriage means is raised to a position such vas that-shown inFig. in which the bottom of a box being stacked is raised above thelevel of the rollers I5. S3 isa double-pole normally closed switch whichmaybe located in position to be actuated (opened) by one of the platformmembers as when the carriage means reaches Vthe loading level, i. e.when` the rollers I3 are aligned with conveyor 1. `Si is a doublepoleswitch` comparable to that employed at S2,

Y i. Ae..havinvg a pair of normally closed and a pair (if-.normally opencontacts, Vwhich is positioned near the top ofthe shaft 2 Where it isactuable byjtheftop edge of a stack which has been brought tothe desiredheight by the placement of the last box on the bottom. As brought outabove itzisunnecessary that the carriage means be raised as high for theengagement of the top of the stack .upon switch Si as it is vto locate abox on the locating rollers I5, it being necessary only toraise thebottom box high enough to clear the locating rollers from under thenextsuperior box (Fig. 4 illustrating such a position), andthen-continue the upward movement enough to carry the-stack of boxesupwardly a short distance-into contact with S4. S5 may comprise afour-pole switch having three sets of normally closed contacts and oneset of normally open contacts, and is preferably located so as to beengageable by one of the platform members 9 in itsf lowermostpositionisuch as that indicated indot-dash lines in Fig. 3). Ss-maycomprise a 61. single-pole normallyopen switch .actuable :by theleverzeat a; point Vinterrnediatge the full line and .dot-.dash .line.positions thereof; .shown in Figlg. L' i In theillustrated .circuitarrangement.. three relays R1, R2. and Re are provided, R1 controlling.

the upVirnovement of the carriage, Rzqcontrolling the zdownmovemenhandRs being utilized in Vvthe operation oflowering the, Vstackonto .the

6I ofRz, thence through line 52 to line lead .6.3.

This .energizes R1. causing line lead 5I to be connected through line64, jumper 65.' contact-:6.6.

f line 6-7, thermal-relay TR1. ,coil `68 of up control switch `assembly69,y thence v .to lline lead. 5:3. The .001156 is then connected. :byoperation of R1,- through movable contact-"I0 of the makebefore-breakcombination lll- 5.3, 54, direct to line 64 which is connected to linelead 5I., holding the relay Riclosed independent of Si so Vlong zas Szand Si remain closed. When the carriage Vfis at the loading level, S3 isheld open, and the lower. (normally closed)l contacts thereof' hold openthe retur-ncircuit for coil 5 3 inasmuch as the latter contacts `are inseries withl S2. For this reason'a lower set of normally open contactsare Yprorvioledjfor S1 i-n position `to Ashunt the latter contactsrof4S3 until the carriage has fmovedupwardly a sufficient amount to closeS3. v

Operation of motor M in lan upfV direction raises the carriage andvitsbox until thev bottom of the box has been carried vabove the locatingrollers I5, at which .position switch S2v is Vengaged,I opening theupper pair of contacts Vand closing thelower pair. .Opening the upperpair of, contactsv opens `the return circuit for .thefcoil 5E of R1,opening the .supply lead at GSand stopping motor M. Closing thelowercontacts ofSz, connects line lead 5I through line .'II to vtheenergizingcontact 'l2 of R2, thence through contact'fline 14 to coil 15,thence througlivline .16 t'o'control'contactll on Ri, through lines'18and '19 through the upper normally closed contacts of Se to linelead`63. Operation of 'Rzcloses the circuit to down switch 80, from linelead 5I through leads 81 .through the lowermost-normally closedcontacts; of Sq, through jumper 82, contact 83V and lead l84 to thermalrelay TR2, thencejto coil 85, causing l themotor M to urun in the"down"'direction.1 Ihis ,lowers the carriage away from the rst boxlocatedl on the locating -rollers I5, and returns Ait to loadingposition, at which timeiSa is opened, opening thereturn circuit for coil'I5 of R2, and de-energizing motor M. f l

*The `device fis now in condition for V'receiving the second'vbox-within the carriage, which closes Si and'causes a repetitioni ofthe operation. Two boxes are Anow supported'on the locating rollers,theiirst resting on top of the second. After a given `number of suchrepetitions, `so kthat a desired number of boxes, sayeight, 'havebeen-supported `upon the locating rollers, and the .ninth box isreceived bythe carriage, the resulting 7 upward movement of thecarriage, afterrengagement' of. the bottom of the eighth box by the topof the ninth, causes the top of the iirst box (on top of the stack) toengage S4. Operation of S4 opens contacts 59, opening the return circuitforl coil-56 of R1, stopping -the upward travel of `the assembly.Operation of S4 also causes nthe lower normally open contacts to close,connecting line lead-| through leads 86.to energizing contact 81 of Ra,thence through contact 88, lead 89, coil 90, lead 9| to the middlenormally closed contacts of S5, and lead 92 to line lead 63. OperationAof R3 causes contact 93 to close, connecting line lead 5| through'leads94 and 95 to energizing -contact 12 of R2, causing the motor M to beopratedrin the down direction and lowering the carriage. Upon operationof Ra, contacts 96 close before contacts 81 and 88 open, and hold R3 byconnection direct to line lead 5| through lead 94 so that de-operationof S4 will not interruptthe downward travel of the carriage. Operationof R3 also closes contact pair 91 of R3 connecting solenoids L1, L2, L3and L4 across line leads 5| and 63, lifting the locating'rollers |5totheir upper most positions, clear of the stack. Solenoids L1--L1represent the solenoidsshown at I9 in the drawings. Contacts 98 shuntthe upper normally closed .contacts of S3. so that opening of S3 willnot cause R11 to be de-energized when'the loading level is reached bythe carriage, which therefore descends 'to its lowermost position(dot-dash lines in Fig. 3), where'Ss is operated. Operation of S5 opensthe return circuit for coil 90, at 9|92, de-operating R3, which in turnde-operates'Rz and stops motor M, Inasmuch as it is preferred that thelocating rollers |51 remain out of'engagement with the stack of boxes atthis lowered position, S5 is preferably provided with a lower normallyopen set of contacts 99 which close to shunt contacts 91 and retainenergization of solenoids L1-L4.- f "When the ,stack is lowered tothislowermost position of the carriage, opening gates 2| by operation ofthe gear and crank assembly 23, the Afloor chain conveyor 5 carries thestaclcaway, and as the lever 24 is releasedby removal of the stack,theswitch Ss is momentarily closed, connecting line lead 5| throughleads |00, normally closed contacts |0|, lead |02 and Vlead |03toenergizing contact 53 Vof R1, starting .an upward movement of thevcarriage, relay R1 holding through lead 54 and contact 10.' Whenthecarriage leaves its lowermost position, it goesV out of contact withSs', opening the 'circuit to the solenoidsL1-'L4. V As the carriageisbrought up to .loading position, S3 is contacted, opening the lowerset of normally closed contacts (in series kwith the normally closedcontacts of S2 and S4) breaking the return circuitfor'coil 56 of R1 andstopping the carriage. In this position there is noA box present in thecarriage, hence S1" will not be operated and the shunt for the lowercontactsof Sais not connected.

It will be appreciated that the specific structure herein shown andabove described is to be considered as illustrative only. and notlimitative upon our invention, the broad scope'of our invention beingdeiined in the subjoinedclaims. For example, while we have shown apreferred form of locating means to hold the stacked'boxes in the shaftas comprising roller members l5, numerous other forms of locatinglatches maybe visualized by another. skilledfin such art, and

may vbe substitutedl therefor vwithout departure from our broad conceptofthe structure.

We claim: e

1. In a box stacker,v the combination of an elevator adapted to bereciprocated vertically between a box receiving position and an upperposition to permit this to receive boxes and elevate the same in theformation of a stack; latch meansv for supporting said stack as it isthus progressively formed; means for delivering boxes horizontally in agiven direction onto said elevator; means forreceiving said stack fromsaid elevator after it is formed and discharging it out of said stackerin the same direction as that in which said boxes were delivered to saidstacker; a. pair of gates disposed alongside opposite edges and in frontof the path along which said elevator operates vertically, said gatesacting as limit stops for individual boxes being fed onto said elevatorand as stack guides; and means operating in timed relation with thedelivery of said stack from said elevator onto said stack dischargemeans for displacing said gates from in front of said stack to permitthe latter to be Idischarged from said stacker.

2. A combination as in claim 1 in which said stack discharge meanscomp-rises a conveyor onto which said elevator deposits said stack bytravelling downwardly below its box receiving, position, said means fordisplacing'said gates being actuated by engagement with the lower end ofsaid stack as the latter is lowered onto said conveyor.

3. In al box stacker, the combination of: an elevator adapted to bereciprocated vertically between a box receiving position and an upperposition to permit this to receive boxes and elevate the same in theformation of a stack; latch means for supporting said stack as" it isthus progressively formed; means for delivering boxes horizontally in agiven direction onto said elevator; means for discharging saidI stackout of said stacker after it is formed; a pair of gates disposed inVfront of opposite edges of said stack as it is being formed to preventsaid stack falling in the direction in whichitisto be discharged fromsaid stacker; and means operating in timed relation with the dischargeof said stack from said stacker for displacing said gates from in frontof said stack to permit the latter to be discharged from said stacker. v

4l. A combination as in claim 3 in which said means for displacing Asaidgates is actuated by vertical movement of the completed stack.

5; A combination as in claim' 3 in which said stack, after being formed,is lowered downwardly on said elevator onto said stack discharge meansand in which said means for displacing said gates from in front of saidstack is actuated by said stack as the latteris so lowered.

6. A combination as in claim 3 in which said means for displacing saidgates from' in front of said stack is actuated coordinately with thedischarge of said stack from said stacker and just prior tothecommencement of said discharge movement of said stack.l

'7. A combination as in claim 3 in which said gates are pivotallysupported on vertical axes and are swung away from in front of saidstack in displacing said gates to permit the stack to be discharged fromthe stacker.

8. In abox stacker, the combination of an elevator adapted to bereciprocated vertically between a box receiving position and an upperposition to permit this to receive boxes and elevate the same in theformation of ,a stack; latch means for supporting said staclr as it isthus progressively formed; means for delivering boxes horizontally in agiven direction onto said elevator; means for discharging said stack outof said stacker, after it is formed; guide means for the ends andbackside of said stack as it is being formed; guide means disposed infront of said stack as it is being formed to prevent said stack fallingin a direction in which it is to be discharged from said stacker; andmeans operating in timed relation with the discharge of said stack fromsaid stacker for displacing from in front of said stack said front guidemeans to permit said stack to be discharged from said stacker.

9. In a box stacker, the combination of: elevator means operating toform a stack in a given vertical path; means for discharging said stackout of said stacker after it is formed; front guide means disposed infront of said stack when the latter is being formed to prevent saidstack falling in the direction in which it is to be discharged from saidstacker; and means operating in timed relation with the discharge ofsaid stack from said stacker for displacing said front guide means fromin front of said stack to permit the latter to be discharged from saidstacker.

10. In a box stacker, the combination of: elevator means operating toform a stack in a given vertical path; means for discharging said stackout of said stacker after it is formed; guide means disposed at the endsand backside of said stack for guiding the latter as it is being formed;front guide means disposed in front of said stack when the latter isbeing formed to prevent said stack falling in the direction in which itis to be discharged from said stacker; and means operating in timedrelation with the discharge of said stack from said stacker fordisplacing said front guide means from a front of said stack to permitthe latter to be discharged from said stacker.

11. In a box stacker the combination of an elevator adaptedV to bereciprocated vertically between a box receiving position and an upperposition to permit this elevator to receive boxes and elevate the samein the formation of a stack; latch means for supporting said stack as itis thus progremively formed; means for delivering boxes horizontally ina given direction to said elevator; a horizontal conveyor fordischarging said stack out of said stacker after it is formed; frontguide means disposed in front of said stack as it is being formed toprevent said stack falling in the direction in which it is to bedischarged on said conveyor from said stacker; means responsive to thestack, being formed as aforesaid by said elevator, reaching a givenheight to release said latch means and to lower said elevator with saidstack thereon to deposit said stack onto said conveyor; mechanism fordisposing said front guide means away from in front of said stack; and amember, responsive to vertical movement of said completed stack on saidelevator, to actuate said mechanism to dispose said front guide meansaway from in front of said stack.

12. A combination as in claim 11 in which said member is disposedbeneathsaid stack and is engaged by said stack as it descends whilebeing lowered onto said conveyor whereby said member is shifted toactuate said mechanism and dispose said front guide means away from infront of said stack.

13. A combination as in claim 11 in which said guide means comprise apair of gates mounted pivotally on axes disposed on opposite sides ofsaid stack as the latter is being formed; and means normally swingingsaid gates into positions in front of said stack to guide the latterduring its formation and prevent it falling in. the direction in whichit is to be discharged on said conveyor from said stacker, said memberbeing responsive to vertical movement of said completely formed stack,to overcome said normally operative gate swinging means and swing saidgates away from in front of said stack.

14. A combination as in claim Il in which said guide means comprise apair of gates mounted pivotally on axes disposed on opposite sides ofsaid stack as the latter is being formed; and means normally swingingsaid gates into positions in front of said stack tov guide the latterduring its formation and prevent it falling in the direction in which itis to be discharged on said conveyor from said stacker, said memberbeing responsive to vertical movement of said completely formed stack,to overcome said normally operative'gate swinging means and swing saidgates away from in front of said stack, said stack responsive membertbeing mounted beneath said stack so as to be engaged by said stack andbe shifted downwardly thereby as said stack is lowered onto saidconveyor.

l5. In a box stacker, the combination of: an elevator adapted to bereciprocated vertically between a box receiving position and an upperposition to permit said elevators to receive boxes and elevate the samein the formation of a stack; latch means for supporting said stack as itis thus progressively formed; means for delivering boxes horizontally tosaid elevator; means for receiving said stack from said elevator, afterit is formed, for discharging said stack from said stacker; guide meansdisposed in front of said stack, as it is being formed, to prevent saidstack falling, during its formation, in the direction it is subsequentlyto be discharged; and means responsive to vertical movement of saidelevator and stack in the stack completing reciprocation of saidelevator, to displace said guide means from in front of said stack.

16. In a box stacker, the combination of elevator means adapted to forma stack in a given vertical path; means for receiving said stack fromsaid elevator, after it is formed, for discharging said stack from saidstacker; guide means disposed in front of said stack as it is beingformed to prevent said stack falling, during its formation, in thedirection it is subsequently to be discharged; and means actuated byvertical movement of said elevator and stack, and operating between thecompletion of said stack and said discharge thereof, to displace saidguide means from in front of said stack.

BRUNER R. DAVES. WARREN L. IRVINE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 158,976 Pfautz et al Jan. 19.1875 1,292,636 Parker Jan. 28. 1919 1,564,536 Davis et al Dec. 8, 19252,266,170 Currie Dec. 16, 1941 2,313,478 Neja Mar. 9, 1943 2,333,479Graf Nov. 2, 1943

